Porsche Carrera 3.8RS (964) ~ 1993-1993

The RS 3.8 was developed as a road-going car so that Porsche could qualify for the GT racing championship with the full-race RSR 3.8 – which race rules demanded be derived from a production model – and appeared after the original 3.6-engined RS of 1992 had gone out of production.

The bodyshell was that of a 3.6 911 Turbo bodyshell with flared front and rear arches (the previous RS had a narrow body). To compensate for the extra weight of the big wings, Porsche fitted unique lightweight aluminium doors as well as the 3.6 RS’s aluminium luggage-compartment lid and thin side-window glass. In fact, despite the wider bodywork, at just 1210kg the RS 3.8 was a full 10kg lighter than the previous RS.

At the rear was a massive adjustable rear spoiler, which was part of the one-piece engine-compartment lid. The spoiler can be set to one of six positions depending on the amount of downforce required.

And beneath this was a 3746cc engine. Based on the 964 unit, the extra capacity was achieved by increasing the bore by 2mm to 102mm, while the stroke remained at 76.4mm.

However, to get the power up from 260bhp to 300bhp, further changes were necessary. Lightweight pistons and rocker arms were used, together with individual throttle valves for each cylinder. Inlet valves were increased in size from 49 to 51.5mm and exhaust valves from 42.5 to 43.5mm, and the ports were polished. The compression ratio was raised from 11.3:1 to 11.6:1 and an additional oil-cooler at the front of the car helped keep temperatures down.

The inlet system used a compact hot-film air-sensor (as featured in the later 993 engine) in place of the restrictive flap-valve of the standard engine, while a free-flowing exhaust with twin tailpipes let the gases escape.

The gearbox was the 964’s five-speed transmission fitted with RS ratios, updated with steel synchronising cones and a limited-slip differential with a 40 per cent locking factor under load (instead of the 20 per cent of the previous RS).

The suspension was also lifted from the Carrera RS, but with revised damper and spring ratings, and larger, adjustable front and rear antiroll bars. The three-piece 18-inch light-alloy wheels were specially made by Speedline in Italy (they have 'Speedline for Porsche' etched into the rims) and were 9-inches wide at the front and 11-inches at the back. Tyres were 235/40 and 285.35 respectively.

Brakes were RS items at the rear and 3.6 Turbo ones at the front. The brake servo and ABS were retained, but power steering wasn’t.

When the car went on sale in Germany in 1993, it cost DM225,000 (which was then about £90,000). That country’s auto motor und sport magazine claimed that 'anyone who buys a Carrera RS 3.8 to use on the road has too much money and too little sense.' However, the car has gone on to become one of the most sought-after RSes of all time, partly because of its rarity, but also because it is such a great machine, both to look at and to drive.

See our dedicated 964 site

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